Alright! So you've displayed interest in Garen. Garen is a wonderful DPS, capable of dealing some heinous damage, at the cost of any real team utility buffs/debuffs that aren't built in items. He has great damage with this build, and also offtank survivability, allowing him to charge into the AoE fray dealing great AoE damage and silencing that awful Fiddlesticks, making his life Hell.

Mind you, this is my first Mobafire build, but I spent a lot of time testing this out. I'm certain of its effectiveness. This was tested for roughly 60 matches (only 2 ever leaving me at less than a 1:1 KDR), and 11 ranked matches (ending with a 9.1/3.1/6.5 average).

Enjoy the read. Its an entensive one. If you like it or have comments or improvement suggestions, im open to them!

Ok, theres a reason my rune page is so simple.

Armor penetration will give you so much armor pen that any champion you fight who isnt building an armor item first will have 0 armor against you until about level 4

"But Rowdy, flat armor pen cant drop people below 0 armor! You'er wasting rune page space! uninstall noob!"

No, no, silly. The armor pen is really more for the end game. When you have 200+ AD, which is all you really need, the 25 armor pen increases your damage by percentages. So the more flat AD you build with items, the more this Armor pen helps late game when your damage is supposed to naturally pan out.

My thinking on the magic resist is that Sunfire Cape covers your armor and your health, hexdrinker gives a moderate amount of MR, and the added MR from your rune page will help you weather the nuke storm when the other team realizes you're actually the one they should be focusing...

Stop laughing. There was nowhere else to put the 4th point in the offense tree. No, AP doesnt help you...

Moving on, the crit % from Deadliness helps you for your autoattacks (which you actually don't use very much except for finishing off crippled enemies and minion farming), but more importantly your judgement can crit. This is how that is calculated:

Judgement does a flat amount of damage per second and 35% of your AD on top. The AD portion of the formula can crit, and is affected by crit damage. So, by the end of this build, your judgement will tick for large damage, and have a 1/3 chance to crit for about 260% damage.

Otherwise, the offense tree gives you armor pen, damage, CD (you are cooldown constrained with this build), and magic pen % for your ult. I dont like to take the attack speed because Garen's auto attacks are just not used very much with this build.

In the defense tree i take the armor and MR and leave it at that. Gives great survivability, done deal.

In utility, the health regen affects your ult, which makes for an even easier laning phase. The ghost spec is a must for my two summor spells of choice.

Just as a note to good League players: Any good player changes their build according to what is necessary to help the team or defend against the other.

If i am laning with a laning partner, my first item is generally Doran's Blade. The lifesteal is damn near negated, but the 100 health and 10 damage helps your already incredibly high base damage at low levels.

If you can, make use of your passive to stay in your lane until you have 2,337 gold. This will allow you to magically come back to the lane with both Boots of Swiftness and your Brutalizer. This is a nasty wake-up call for any enemies who disregarded you at first. With these 2 items, even equal level tanks building armor will take nearly full damage, and very high damage at that, and no one under the sun will be able to escape your judgement without summoner spells or escape abilities.

(Note: I dont build my Brutalizer into the ghostblade until its the last gold i can spend. Not a very helpful upgrade for this build for the 1350 gold cost.)

After you build your movement speed and early damage, you'll want some survivability. Grab your sunfire cape to give you a nice pool of health and protect against those nasty competing AD champs.

Now, to continue survivability and damage at the same time, a Hexdrinker will supplement your MR runes, build you some damage, and save you with a 300 hit point spellshield every time.

Even thought i have Soul Shroud and Infinity Edge in my build, the last 2 items are your items to pick and choose from. Here is a list of all the effective items I've tried:

Infinity Edge: I generally get this item last, if anything, but I get it often. Its very high damage, and makes your judgement that much more effective end-game.

Soul Shroud: This improves your survivability even further, if teams are still trying to focus you out of fights. Remember, with your already decent MR and Armor, any your effective HP against either type of damage multiplies very quickly. The CD reduction helps you use your abilities that much more often, if thats a problem for you, and helps your team out with the aura. There is not a champ in the game who doesn't get benefitted by cooldown reduction even just a little bit.

Shurelya's Reverie: This gives you a nice bundle o' health, CDR, and a HUGE teamwide movement buff to complement your already killer movement speed. With ghost, Shurelya's, and Decisive strike, you can catch a ghosting and ulting Master Yi anyday.

Bloodthirster: This is an ok item. The damage on it is sick, if you can farm up the minions (trust me, you can. Hit E like 3 times and done.) The lifesteal also affects auto-attacks as well as your Decisive Strike. So, if you're hitting for 700 damage on Decisive Strike, it can turn out to be a decent heal, too. However, for the gold and the item slot missing, I wouldn't suggest it among some other items.

Last Whisper: I would strongly suggest building this if there are 2 or more champions on the opposing team building more that 200 Armor. % Armor pen is calculated AFTER flat armor pen, so build flat armor pen (which your runes and Brutalizer does) actually reduces the amount of armor pen Last Whisper gives you. If there are 2 or more AD tanky champions on the enemy team, though, this can end up cutting 100+ armor from both of them. A fantastic item in that case. At any point, the 40 damage it gives never hurts...

Guardian Angel: You health just doubled. Tower dive, backdoor, dance on the enemy team's landing pad. If you're doing well in a game, this guarantees continued success, but only after you've already built good damage items. The only downside to this item that i see is that it can take the place of another damage item.

Force of Nature: This gives movement speed to help your Judgement catching along, multiplies your passive into ungodly amounts of health regen, and makes caster incapable of touching you. However, on that note, 2600 gold is a lot to spend for absolutely no damage increase. I would only suggest building this if you already do enough damage or there are lots of very high damage caster on the enemy team.

Banshee's Veil: This is an acceptable item in any game, for any reason. MR, health, and a free spell on you. What not to like? The only downside is, like always, it takes the place of your precious damage items.

Two ways to do this, so far as i see, depending on your lane type.

Laning with another:

Judgement
Decisive strike
Judgement
Courage (1 POINT ONLY)
max Judgement
max Decisive Strike
take ult when possible

Solo laning:

Judgement
Courage
Judgement
Decisive Strike
max Judgement
if you are still having problems with survivability, take as much courage as is absolutely necessary. Otherwise, keep going up in Decisive Strike. Remember, you're building for Offtank/Damage late game. Taking too much courage and not enough Decisive Strike will gimp your damage later.
Ult when possible

Remember to change your strategy to suit your laning partner' needs, but these tactics generally work no matter what.

Laning with Another:

Wait at the further edge of the brush closest to your turret. If your partner has some sort of line-of-sight or clairavoyance, you can also move to the edge of the enemy brush closest to their turret if you like. Stand at the very edge.

Do not judgement into their brush. You can get yourself into trouble and unless you start judgement when you are already in their brush, you may not do full damage.

Demacian Deathbrush Tactic

Wait for either of them to come to your brush, and RIGHT before they enter your brush and see you, begin Judgementing. Here are the two reactions you might encounter:

"OMGGARENJUDGEMENTIMBONED. Run!"
If this is the case? Simply walk with em'. Since you let them stand on top of your character before you started Judgement, even if they have boots, they wont make it out of range before you're done with all of your damage. They are forced to flash or escape through other means.

"Whateva. Garen is a tank, right?"
Lol. You're 1/0/0. Maybe even 2/0/0. GG.

(Protip: If you are aware that there are champion waiting at the edge of the crush neighboring yours or are otherwise close to where you are standing, you can flash on top of them and judgement immediately. It has the same effect, but allows you to initiate. The downside is that you use one of your escapes in case things go bad.)

If it turns out the beginning gank goes awry and they beat you up, ghost or flash out, stand at your tower, and you'll be at full health because of your uber passive by the time minions arrive.

Throughout the laning phase, keep using this tactic until the enemies simply cant take any more abuse. When they are pushed back or afraid of you, leave the bush to last hit minions with Decisive Strike, or farm whole waves with Judgement.

Minion farming is incredibly effective on a Garen. Remember that before judgementing a minion wave, you can place yourself in the space between the melee minions and the caster minions and hit all of them with each tick.

Judgement (rank 1): Drop entire minion wave to halfish-health. Bleh, but it makes for easy last hitting with one or two melees and helps your partner farm.
Judgement (rank 2): Drop minion waves to nearly dead, allowing you to melee them all to death with one hit each, or let your partner pick up some of his own.
Judgement (rank 3): Will farm entire minion waves with the full 3 seconds.

Decisive Strike is very effective for picking up last hits, but remember that because you are cooldown constrained, using all of your abilities to farm minions leaves you worthless when enemies initiate you or your partner. Be wary of where your enemies are at.

When you get your ult, your behavior should change minimally. Use your ult ONLY when you are sure it will kill the person you are beating on, as its on a long CD at rank 1, and is extremely useful for farming your build early.

If there is a champion in your lane with hitpoint that are low enough to ult or very close, you can pop Decisive strike you chase them faster than they can run away, deal the damage of Decisive strike just to make sure, and THEN ult to seal the deal.

Remember that Courage can be popped to tank turret shots with very little repercussion, but be wary of disables that will keep you in turret range for more time than is absolutely Necessary.

Solo Laning

I'll keep this much more concise. Try to tower hug until you're sure of how harrassable you are with your enemies, and decide upon a defensive or offensive strategy.

Defensive:

If you're unsure of how to stay healthy because you're versing that super aggressive Caitlyn/MF duo, take maybe 2 or 3 points in courage, max Judgement as always, and keep at least one point in decisive strike to help last hit. Never let them starve you. If you have to extend a little bit to keep getting XP, do so, and keep your fingers ready to pop Courage and GTFO.

Offensive:

If you've found that you can stay alive for a good amount of time with some extension or you can get away readily, go ahead and take the skill sequence as if you were laning with someone else. Your 2 second shield should be enough to keep you alive when you're extending, and if you not you can rely on summoner spells. This way, you can farm minions much more effectively, and when you get the chance you can silence, judgement, ult, and leave as you please.

In a Teamfight, you can strive to fulfill a number of roles:

1. Use courage to take a large bit of damage from focusing nukes so that your chewier teammates have a safer battleground to play on.
2. Silence the most dangerous Non-Right-Click champion you are versing. This is generally a caster of some sort. Very high priority targets are Katarinas mid-ult, Fiddlesticks BEFORE he ults, kassadins who try to get away, etc...
3. DONT BE THE TANK. Let the real tank do the initiate, but try to feign higher prioritization when it comes to the enemies targeting order. This is easier said than done. Remember, you're a toughie.
4. If you cant get the enemy team to put some hate on you, take advantage of this by diving in behind the tank and dealing some hateful, hateful damage. Expect them to target you the next teamfight...
5. Eat their chewies. A good Garen combo is generally wasted on tanks or tanky champs. If you can, kill as many as you can just using Decisive Strike and Judgement, then save your ult to make damn sure the enemy tank dies. Because your ult hits harder per point of health missing, it is incredibly effective for executing tanks. Be mindful of how much MR they have. Ulting Galios is not advised.
6. Leave no survivors. Make good use of ghost, Decisive Strikes movement speed, Shurelya's, Youmuus, and any other team buffs available to catch any carries. You have NO excuses for not being able to catch them. a ghosted, Decisive Striking, Shurelya's, Youmuuing Garen is VERY hard Garen to get away from.

My overall recommendation is always ghost and flash, however...
Here's a listing of each spell and its effectiveness:

Exhaust: This is certainly an acceptable spell. Not my favorite, but great if you're good with it.

Ghost: I use this spell all the time. This allows you to catch people, stay in range with
Judgement, get away, and run from other lanes to teamfights in a jip.

Heal: Not super effective, but can keep you alive to keep dealing death, so not exactly awful.

Revive: This just isn't that helpful to Garen. With this build, i damn near never die, so this is generally not a useful spell.

Smite: You ain't junglin', hun.

Teleport: This can be great for helping about the team. You can use it to port to lanes that are overrun with minions or are getting backdoored and chase down some suddenly very distraught Tryndameres and Master Yis.

Cleanse: Garen's survivability makes him generally able to survive a couple CCs, so this really will only save you in some situation getaway moments. Not as useful as I'd like, but not useless.

Fortify: I love a team player. Use this if you are comfortable sacrificing escapability/damage to save your team.

clarity: Lol. you're gonna run into a lot of queue dodgers when people see you using this. Not recommended as Garen doesnt use mana.

Ignite: Honestly, I never see a point to this except for in the first 6 levels of the game. It can help finish off a kill after your abilities are used up, but finishing champs off with your ult is like your signature thing.

Clairavoyance: See fortify.

Flash: This, in my opinion, is an absolute MUST HAVE. It allows you to flash on caster before they know whats happening to silence them, removing any escapability they might have had, and judgement them into nonexistence. This is just too helpful to not recommend

When you get the feel of Garen down, you can use this idea as a thumb rule:

"If i can kill any chewy simply with Decisive Strike and Judgement, then my damage is enough. Past that, survivability and CDR can only multiply my effectiveness."

If you can melt chewies (I only ever need about 200ish AD at level 18 to accomplish that goal), then you can beat down tanks or tanky champs in good time, and use your ult to seal the deal. With this build, the absolutely worst of worst matches i play is never less that a 1:1 KDR ratio. An average match for me is usually 1.5:1 or 2:1. Even if you get stuck on that delicious feeder team of all fiddlesticks', your survivability will keep you alive enough to always get in and out just fine.

Good luck!